88 capri 2.3l ford resistor wire, overheated coil

[Lgbnme]

• Reposting. I'd like to breath new life into this old thread hoping some of you still belong to this page. 1999 Capri 2.3l ford Motor. Having the same issue but I think I am one step further. I had an old issue where the boat would only fire while the key was in the crank position. Thanks to many of these old threads on this page I concluded it was the resistor wire (only 4 volts at the coil) so I cut it out and put in a new coil with a internal resistor. Now I'm back up to 9volts at the coil and she runs and starts great! I find however the coil now overheats and shuts down while out on the water. I swop out the coil and she runs again. I'm so frustrated I think I'm going to just put in a resistor block and an old unresisted coil and try that. What are your thoughts my wise men?

 

[Maclin]

First observation is that full 12v should be seen at the Positive coil connection now with the internal resistance coil. This too low volatage may be affecting the coil's behavior as to overheat and shutdown. In your original setup, only having 4v before at the coil with resistance component in the circuit coil shows that you may have other pieces in the circuit providing their own resistance.

Outdside of that, basically Two things were changed, and new problem pops up.

Definitely worth the trouble to re-install resistance component, and go back to coil that depends on external resistance. Just be sure the voltage at the coil is 9v or 12v depending on if points are open or closed. If it is 4v then the resistance component is not correct or there are other points of resistance in the circuit in play.

 

[Lgbnme]

Thank you for taking the time to respond. I really appreciate it. My origonal voltage checks on the coil were on the neg side of the coil. I did not know there was a resistor wire running the show at the time. My readings were 4.8v going to the points when closed and 12v with points open. After research I found there should be between 8 and 9v going to the points and there was a resistor wire governing the voltage. But now after reading your response I realize the the resistor wire is before the coil not after. I feel kind of silly because I've had the harness in my hands a thousand times and even cut out the resistor wire and soldered in a straight wire from the starter relay where the resistor wire originated from TO THE POS SIDE OF THE COIL. Im so stupid. Of course my next question is what size resistor is needed? How are they marketed? 8-10 ohm, 10-12 ohm? How will I know which to order?

 

[Maclin]

Ballast resistance is lower than that, usually in the 1.5 to 3 ohm range if memory serves. Replacement coils should have a spec sheet or other way to look up what they expect. But a standard replacement automotive 12v coil specifying external resistance will work with anything in that range, usually not a problem when using standard components.

In your case finding original resistance wire, and going with a standard automotive 12v external resistance coil should work.

Having typed all that in, how "positive" are you that the internally resisted coil you tried was wired in properly? Do you have new points in, gapped correctly, with a good condenser?

 

[Lgbnme]

My first inclination was to replace the resistance wire until the parts guy laughed at me. So I said how about a coil with a internal resistor? That I got.
I went home thinking I had this beat. Straight gauge wire from the ignition side of the starter relay to a internally resisted coil. Boat fired right up and ran great till I got it out on the water. I came to the conclusion the coil was overheating because when it died out on the water I swopped out the coil with the old coil and it fired right up and brought me to safety. That told me I had a overheat/breakdown condition on the ignition system, specifically the coil. Having it restart after a coil swop confirmed this and eliminated the points or condenser as the culprit. The points and condenser were the first thing changed when this problem first arose. Points gapped as per the manual. Cap, rotor, wires replaced as maintenance.
I believed I could do away with the resistance wire by using a internally resisted coil. I still do not understand why the coil would breakdown if it's designed for 12v and I'm putting 12v into it. Believing the internal internal resistor would reduce the voltage down to 8 or 9v to the points actually worked. I tested it. I started with 4v at the points before this and had a no start condition in the beginning.
Now I'm going to find a block resistor and put it in line before the coils positive side. That should reduce everything before even getting to the coil like the original resistor wire did. Just gotta find one

 

[Lgbnme]

Also to add to my above post, I went as far as to replace my new napa coil with a Accel super coil hoping to eliminated the breakdown of the coil. It didn't help. Same issue when hot.
here are the specs:

Super Stock Coil; Primary resist 1.4 Ohms; Secondary 9.2 k Ohms; Turn ratio 94:1; Max voltage 42000V.

 

[Lgbnme]

Went to napa and picked up a non-internal resistor coil and ballast resistor I think it was 1.8 ohm. I'll let you know how it works out. My only thought is if that's not enough resistance I'll have to mix a internal restore coil with the ballast resistor to get the 3 ohms. But, I don't want to get ahead of myself. Lol

 

[Maclin]

Should be 1.1 to 1.5 ohms. Forget the 3 ohms I mentioned before, sorry!

 

[Lgbnme]

Update: I installed a matching block resistor and coil. I have 14v battery voltage going in and 11.8v going to the coil. No 6-9v. Wrong resistor?

 

[Lgbnme]

14v going in to the resistor. 11.8v coming out the other side of the resistor going to the coil

 

[Maclin]

I would be fine with that.

 

[Lgbnme]

The coil from napa IC12SB and resistor ICR13 (1.8ohm). I understand the coil is 1.5 ohm internal so I'm looking at just over 3ohm of resistance. I noticed the coil is cool to the touch now. But I'm a little gun shy to take her out again. Lol.....
so leave it at 11.8 volts? Not 6-9volts? I'm afraid if I put another resistor in line to bring it down to 9v I'll lose amps.

 

[Maclin]

It takes current to build spark. Those readings are just fine. The ballast is in the circuit for life of points, and also to help balance the circuit and earn it's moniker (Ballast). Electromotive force can get a little wild when electricity is used in coil/transformers like this. The ballast acts like a kites tail.

 

[Lgbnme]

Maclin I think I found the issue. The reason why I can't get the voltage to the coil down with the 1.5 ohm resistor and 1.5 resistant coil is the voltage regulator is going bad. It's overcharging. Since secondary power is tapped from the back of the regulator and with a fully charged battery it's still pumping out 14.5-14.9 volts it's no wonder why I cant get the voltage down past 11 volts. If the regulator was working properly it would be around 13-13.5v charge. That would bring me down to the 9v range out the resistor to the coil. That explains why the original resistor wire stopped working. Once again I failed to look at the big picture. I hope this post helps someone down the road!

 

[Lgbnme]

Replaced alternator. Same issue.... back to square 1

 

[froggy1150]

The way a ballasted coil works is its a balanced charge/dump scenario. For a coil to work properly it needs to charge to "field saturation". Then when the negative is lost the field collapses and can no longer hold the high tension side and then it "fires". Repeat. The dwell angle and ballast resistor both control over saturation. When it's charged to much the coil will get hot and burn. In older cars you had a direct wire without resistance from starter solenoid that was active during starting to compensate for the voltage drop during cranking and then in run it would switch to resisted power. You need all three.... the right ballast, correct voltage and dwell. To low of saturation = weak spark. To much and coil will:flame:. I hope this helps

 

[froggy1150]

Also 14.5 volts from alt isn't to much. High 15s and up is where I would worry

 

[Lgbnme]

Thanks froggy. I'm going to check the dwell, plug gap and timing. I've been tossing and turning over this. I'm going back to basics and checking the dwell is all can come up with. I've even put resistors in series trying to get the voltage to at least 10v but it won't run. New points, coil, condenser, alternator and resistor. I hope dwell and timing works.

 

[Lgbnme]

Dwell was all over the place on acceleration. I pulled the distributor, disassembled and cleaned the centrifuge. Pit it back in, I can't set the timing. Marks are bouncing. Put it in gear, set the rpm to 650 like it says in the manual. Put it back in neutral and try to set the timing but it wants to stall when I get it near 10 degrees BTC. It's idles best at around 20 degrees BTC. Thoughts?

 

[Lgbnme]

Side note , dwell stopped bouncing off the chart on acceleration after I cleaned up the centrifuge. Now it only moved a few degrees on acceleration. Like it's supposed to. I'm using a dwell meter designed for 6 and 8 cyl engines. I understand you are suppose to double the 8 cyl reading which is reading 19 degrees on the meter so my dwell is 38 degrees.